Pt/electroconductive carbon anode materials are representative electrode materials to be used as polymer fuel cell-oriented electrode materials. Although such electrodes have exhibited higher electrode activities, they have been subjected to such restriction to necessarily use high purity hydrogen as fuels. It is known that when a small amount of combustible impurity is mixedly present in a fuel to be used for power generation by a fuel cell, the combustible impurity component is combusted on a surface of platinum (Pt) to generate gas components such as carbon dioxide (CO2) and carbon monoxide (CO), such that even an extremely small amount of CO strongly adsorbs onto the Pt surface to considerably deteriorate an activity of the Pt surface (patent-unrelated reference 1).
As such, it has been conventionally considered to use high purity hydrogen as a fuel for a fuel cell. However, it is difficult to keep and utilize high purity hydrogen in homes, thereby bringing about difficulty in widespread use of fuel cell systems.
To solve such a problem, it has been attempted to disperse a metallic element such as metallic ruthenium (Ru), metallic iron (Fe), and metallic manganese (Mn) in a Pt/electroconductive carbon anode material, to thereby adopt a combustible alcohol such as methanol or ethanol as a fuel (patent-unrelated reference 2).
Although much hydrogen and CO are generated on a Pt surface in case of adoption of such alcohol as a fuel, the generated CO is oxidized on the added metallic element such as Ru, Fe, or Mn and converted into CO2, thereby enabling utilization of a fuel cell over a long period of time without deteriorating a higher electrode activity of Pt.
Unfortunately, since Ru metal to be added is expensive, its activity for oxidizing CO is still insufficient, and other inexpensive compounds such as iron oxide, manganese oxide and the like also fail to exhibit activities for oxidizing CO as high as Ru, there has not been practiced an anode material including such Pt/second component/electroconductive carbon yet.
Referenced Literature/Publication:
Patent-Unrelated Reference 1: M. Watanabe, et al., Denki Kagaku, Vol. 38, pp. 927-932, 1970, Electrochemical Society of Japan; and
Patent-Unrelated Reference 2: Masahiro Watanabe, Catalysis and Catalyst, Vol. 44, No. 3, pp. 182-188, 2002, Catalyst Society of Japan